A motor vehicle such as an automobile or a van typically includes air conditioning apparatus which cools the passenger compartment of the vehicle when its engine is running. Such vehicle air conditioners typically employ a standard refrigeration cycle in which a refrigerant such as Freon is passed between gaseous and liquid states for purposes of cooling. In known air conditioning systems, an air conditioning compressor is driven by a pulley and belt connection with the vehicle's engine. The compressor circulates refrigerant through a condenser, an expansion valve and an evaporator. The expansion valve substantially reduces the pressure and temperature of liquid refrigerant which is supplied by the condenser and the evaporator converts the liquid of the expansion valve to a vapor of relatively low pressure and temperature. The vapor is then passed to the compressor for circulation to the condenser. A blower fan operates with the evaporator to provide cool air for the passenger area of the vehicle.
In order to provide a viable air conditioning system, the engine of the vehicle must be sufficiently powerful to move the vehicle and to provide an additional increment of power sufficient to operate the compressor of the air conditioner. The relatively large power output of the engine is thus effectively used to move the vehicle and to provide a comfortable operating environment for its occupants.
If a vehicle is parked for extended periods, it is often not possible to continue running the engine to maintain a comfortable temperature in the passenger compartment. For example, if the vehicle is stationary, the engine may tend to overheat while operating in relatively high ambient temperatures. Also, the idle setting for the engine may not be sufficiently high to keep both the engine and air conditioning compressor running when the vehicle is parked. Accordingly, it may be necessary to accelerate the engine and thus generate undesirable noise and noxious fumes to maintain operation of the air conditioning system.
Moreover, if the driver leaves the vehicle, the engine must be turned off for safety purposes and also to avoid wasting fuel. When the driver returns, the vehicle will be uncomfortably hot for an extended period during which the air conditioner operates to cool the heated air.
Typical vehicle air conditioning systems also have operational disadvantages in recreational vehicles, such as vans, which have a living compartment. It is often desired to park such vehicles for hours at a time while the living compartment is being used, for example for sleeping. Air conditioning is typically not provided while the van is parked, because operating the engine during such periods is noisy, relatively unsafe and is wasteful of fuel.
Accordingly, it is an object of the invention to provide a relatively simple and reliable auxiliary engine which drives the compressor of a vehicle's air conditioning system and maintains a comfortable temperature within the passenger compartment of the vehicle when its main engine is turned off.
A further object of the invention is to provide such an auxiliary engine which operates by internal combustion and utilizes the cooling and exhaust system of the vehicle's main engine.
Another object of the invention is to provide such an auxiliary engine with a throttle control which automatically maintains a predefined RPM output for operating an air conditioning compressor.
A further object of the invention is to provide such an auxiliary engine with an exhaust system which is connected to the exhaust system of the main engine with a baffle plate which prevents exhaust gases from backing up into the main engine and which directs the gases of the auxiliary engine through a catalytic converter and muffler of the vehicle.
It has been suggested that an auxiliary engine may be provided in a vehicle to operate the vehicle's air conditioner. For example, as disclosed in U.S. Pat. No. 3,844,130, an auxiliary power system can utilize an electrical generator located in the trunk of an automobile to operate an auxiliary electric motor which powers the compressor of an air conditioner. This proposed system has limited practicality for passenger automobiles and recreational vans, because a relatively large amount of space is required to generate the electrical power that operates the auxiliary electric motor. Moreover, the disclosed system is relatively inefficient as a result of energy losses which occur when a mechanical drive system such as an internal combustion engine generates electrical energy which is in turn converted to mechanical energy by an electric motor to drive a compressor.
It is therefore an object of the invention to provide a compact auxiliary internal combustion engine which can be easily installed in the engine compartment of a vehicle to directly drive the compressor of the vehicle's air conditioning system.
A further object of the invention is to provide such an auxiliary engine with a jack shaft which couples power from the engine to the compressor.
Another object of the invention is to provide such a jack shaft apparatus which is geared to convert an optimum RPM output of the auxiliary engine to an optimum RPM driving input for the compressor.
In the system of the U.S. Pat. No. 3,844,130, an auxiliary fan is provided to cool the radiator and condenser of the air conditioner when the auxiliary power system is operating. However, cooling is not optimized, because the fan directs its flow of air to only a portion of the condenser and radiator. It is therefore desirable to provide a shroud which will direct the air of the auxiliary fan over the entire face of the radiator and condenser and which will not block the flow of air from the fan of the main engine when the auxiliary fan is turned off.
Accordingly, it is an object of the invention to provide a shroud which directs the flow of air from an auxiliary fan over the face of the radiator and condenser of a vehicle when the main engine of the vehicle is not operating.
Another object of the invention is to provide such a shroud which automatically opens to allow air to bypass the auxiliary fan and to flow through the condenser and radiator when the main engine is operating.
Automobiles and other vehicles typically include a heater core and a fan which directs air through the heater core to heat the passenger compartment when the ambient outside temperature is uncomfortably low. The problems of heating a vehicle in this manner with the vehicle's main engine are similar to the problems discussed with repect to operating the compressor of an air conditioning system with the main engine. Thus, it is desirable to provide an auxiliary power system which will heat the passenger compartment of a vehicle, without operating the vehicle's main engine.
Accordingly, it is an object of the invention to provide an internal combustion auxiliary engine which powers the compressor of a vehicle's air conditioner and also includes a water cooling system which provides a flow of high temperature water to a heater core to heat the passenger compartment of the vehicle when the vehicle's main engine is not running.
Recreational vans occasionally carry a water storage tank which is used as a convenient source of water for occupants of the van. Such tanks either do not provide heated water or require a power system external to the van to heat the stored water. It would be desirable in such vans to provide a relatively simple and efficient means within the van for heating water in the tank.
Accordingly, it is a further object of the invention to provide an auxiliary engine which will heat water in a storage tank of a vehicle.
Another object of the invention is to provide a system for automatically controlling valves which connect the water cooling system of a vehicle's auxiliary and main engines to selectively heat a water tank and the passenger compartment of the vehicle.
Although an auxiliary internal combustion engine may be independently designed for the system of the invention, it is advantageous from a manufacturing standpoint to utilize a commercially available engine to provide the functions of the invention. It has been found that a 10 hp marine outboard motor is suitable for powering the compressor of typical vehicle air conditioning systems. Such motors are sufficiently small to satisfy the space requirements of the invention and have sufficient power to achieve the objects of the invention.
Accordingly, it is an object of the invention to utilize the power head of a marine outboard motor as an auxiliary power source for operating a vehicle air conditioning and heating system.
It is a further object of the invention to provide a means for modifying the operation of such an outboard engine, so that it can operate in a horizontal rather than a vertical orientation.
These and other objects of the invention will be appreciated by a review of the drawings and of the following detailed description of preferred embodiments.